[Elecraft] KPA100 tools

[Don Wilhelm]

LS,

The tools listed in the KPA100 manual are quite sufficient.
To set the PA bias, you do need a means of measuring the current rise 
for the PA idle current, and most DMMs will suffice - you will have to 
measure a current rise of 400mA.  I use a dedicated DMM on the workbench 
set on the 10 Amp scale for that purpose.  Since you are doing only one, 
a dedicated DMM for that purpose is not economical.  Use your existing 
DMM connected to measure current.

The only other things I use are a precision 25 ohm and precision 100 ohm 
dummy load.  Those 2 dummy loads allow me to more accurately set C1 than 
I am able to do by measuring the DC voltage null as instructed in the 
manual.  When the wattmeter bridge is correctly balanced, the SWR shown 
by both those loads will be the same.  After adjusting C1 so the SWR 
reading for both loads is the same, I can easily set the REFL pot 
exactly for a 2.0 SWR.

If you do not have the capability to produce a 25 ohm and a 100 ohm 
dummy load, then simply follow the instructions in the manual, and it 
will be close enough for proper operation.  The KPA100 throttles power 
back if it detects an SWR in excess of 2.0, so this is not a critical 
setting and those tools are not required - this is just a refinement 
that I do on my repairs.

73,
Don W3FPR


On 3/21/2016 4:06 PM, lstavenhagen wrote:
> Hi all,
> And speaking of the K2... I can't recall if I asked this several years ago
> on my first K2 build when I was contemplating this exact same question the
> first time, :),  and I couldn't find this specifically in the reflector
> archives either.
>
> Are there any specific tools for building/aligning/testing the KPA100
> _other_ than the ones listed in the manual that are either required or very
> strongly suggested?
>
>